滑动窗口

这是一道单调队列的模板题
参考链接

#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6 + 10;
int a[maxn], du[maxn];
int n, m;
int main()
{
   
    while (~scanf("%d%d", &n, &m))
    {
   
        for (int i = 1; i <= n; ++i)
            scanf("%d", &a[i]);
        int head = 0, tail = 1; //定义头指针和尾指针
        du[0] = 1;
        if (m == 1)
            printf("%d ", a[1]);
        for (int i = 2; i <= n; ++i)
        {
   
            if (i - du[head] >= m && (head < tail))
                head++;                                    //如果区间长度大于m则把最前面的删除，也就是head++操作
            while (tail > head && a[du[tail - 1]] >= a[i]) //判断队尾元素是否大于刚刚进来的元素
                tail--;                                    // 如果是就把队尾删除，一直到前面一个元素小于等于它为止
            du[tail++] = i;                                //记录最小值位置
            if (i >= m)                                    //窗口移动的过程输出最小值
                printf("%d ", a[du[head]]);
        }
        printf("\n");
        head = 0, tail = 1;
        du[0] = 1;
        if (m == 1)
            printf("%d ", a[1]);
        for (int i = 2; i <= n; ++i) //最大值同理
        {
   
            if (i - du[head] >= m && (head < tail))
                head++;
            while (tail > head && a[du[tail - 1]] <= a[i])
                tail--;
            du[tail++] = i;
            if (i >= m)
                printf("%d ", a[du[head]]);
        }
        printf("\n");
    }
    return 0;
}